Waste plastic discarded from homes and elsewhere has so far been incinerated or dumped in landfill, but this has led to societal problems such as negative impact on the global environment and a lack of landfill sites. Consequently, measures aimed at recycling waste plastic have been adopted in recent years, and there is now a need for recycling methods and apparatus that were not really considered necessary in the past.
The above-mentioned waste plastic is contained in large quantities in used consumer electrical products. In particular, plastic is used in the housings of television sets and personal computer displays, so there is a need to recycle these plastics.
In material recycling, which is one recycling method, plastic products have to be precisely identified and sorted for each type of plastic, and any dissimilar materials that are attached to the plastic products have to be eliminated. This is because if the plastic is recycled while it still contains a dissimilar material, this will adversely affect the quality and properties of the regenerated plastic. For example, a television set or computer display housing includes not only the plastic of which the housing itself is made, but also paper labels and cloth speaker netting that are applied with an adhesive. Furthermore, plastic parts made of different materials, such as switches, or metallic speaker netting may be attached. Up to now, to eliminate these dissimilar materials, the worker had to cut them off with a tool or remove them by applying heat.
Patent Document 1: Japanese published unexamined patent application No. 2001-89021